1. Field of the Invention
The present invention relates to various improvements in equipment, apparatus and devices for handling and placing plugs and plants into soil and growing mediums.
2. Description of the Relevant Art
To achieve maximum economic returns it is necessary to plant plants at a precise depth, these plants are to be vertically positioned and at a uniform, precise distance plant to plant along the row, with each position being occupied by a live plant.
To achieve this in the past it has been necessary to have a substantial input of hand labour straightening plants and hand planting plants into positions not being occupied by plants. It has been found that the degree in which soil has been compressed around the plug will seriously effect the development of the root system, plant growth, and ultimate crop yields. If, for example, the soil is loosely filled around the plug, then a partial form of aerial root pruning occurs slowing down the speed at which the roots can spread. If the plug is positioned so that the top of the plug is above the top of the soil, then a form of wicking occurs causing the moisture that rises upwardly into the upper regions of the plug by capillary action, to be totally exposed to wind and sun which rapidly removes the moisture from the plug causing water stress, wilting, and in extreme cases, the plants death.
For the majority of cases, a shoe opening device is used to separate the soil ready to receive a plug containing a plant. By the nature of a continuous trough being formed in the soil it has proved difficult to properly compress the soil immediately behind and in front of the plug. This is further exacerbated by high speed planting which causes the soil to act like the wake behind a speed boat with the shoe travelling at a greater forward speed than it takes for the soil to envelop the plug. Also the greater the speed, the longer the distance is behind the soil opening device before the soil closes behind the xe2x80x9cwakexe2x80x9d and totally envelops the plug.
Traditionally a mechanical linkage attached to a pusher block pushes out the plug and plant, but the pusher block only extends to the rear edge of the furrow opening shoe. This has been done to avoid contact with the soil and to avoid the transport of the soil back inside the shoe. However the result traditionally is that the plug is not handled beyond being placed loosely in the open trough following the forward moving shoe and results in very uneven placement of the plants.
Traditionally a timed mechanical pushing assembly works proportionate to the forward speed of the machine and must be mechanically timed to coincide with the variability of the drop speed of the variable weight and size of the plug and plant. Previously and traditionally, the back of the soil opening device or shoe, has remained open allowing the premature escaping of the plant and inaccurate placement and possible dislodgment of the plant by external wind. This problem has been partly addressed in Williames International Patent Application No. PCT/AU97/00893 now U.S. patent application Ser. No. 331906, using a vertical guillotine door, but on this basis there are limitations to the speed in which plants are contained and released, with the bottom half of the door clearing the top of the foliage and re-shutting in time to properly contain the next plug and plant. For high speed planting, this system precludes the possibility of placing more than two plants per second when planting tall plants.
Traditionally the means of leveling and compressing the soil around a plug has been by means of large diameter steel wheels or a ski. The steel wheels by their nature of rolling resistance have to be of a large diameter to support the weight, and consequently preclude the ability to put a series of machines side by side for close row spacings. Alternatively, a ski is used which is dragged across the surface of the soil, but is prone to relatively rapid wear and it is undesirable to have a ski dragged across muddy fields due to the rolling up of the surface of the soil. This, by its nature precludes the use of the machines on wet days and shortens the time frames that the machine can be used on saturated soils.
In some crops, e.g. lettuce, the accuracy of the top of the plug relative to the top of the soil has a profound impact on the volume and quantity of marketable lettuce heads produced. If the plug is below the soil level two very serious things occur:
1) The soil envelops the lower portion of the lettuce leaves which can cause crown rot, with the consequent loss of the complete plant;
2) If the plant survives the outer leaves of the young lettuce plant are unable to flatten out in a semi horizontal position, but instead are held in a firm angular position. This prevents the subsequent lettuce leaves from obtaining the correct profile to form a largely circular lettuce head, and instead is formed into a looser high crowned oval shape similar to an American or Australian football. A lettuce head formed in this manner is totally unacceptable for commercial usage and is left in the field, mostly as wastage.
A similar effect to that described above, is also caused if the plug and plant are planted on a semi inclined plane, with part of top surface of the plug protruding above the surface, and part of the top surface of the plug buried under the surface of the soil.
Whether it is a machine in which the plants are fed by hand, dropped by cups, or fed by semi automatic or automatic mechanisms, all these plants are affected by the degree of water saturation of the root and soil mass. Also the weight of the plug varies substantially throughout the day due to evaporation, transpiration of moisture in the plugs and the effect of rain showers on the plugs and plants in trays waiting in the field to be transplanted. This weight variation effects the speed of which the plug and plant falls and the inertial effect of the horizontal transfer of the plug from the planting shoe. The size and length of the foliage has a substantial effect on the ability of a plant to remain vertically erect due to inertial forces involved in the movement through the soil, wind resistance on the foliage at the time of rapid vertical and horizontal movement during plant/plug transfer stages, and also any external wind sources.
Traditionally there have been three methods employed to handle plants from their growing containers to the planting position and into the ground.
1) Plants are manually pulled from the container, separated by hand and either manually placed into grippers or dropped down a tube.
2) Plants are manually removed from the growing containers, separated manually and placed into rotating cups which release the plants at the correct position and the plants fall down a tube.
3) Singular plants are mechanically ejected from the container one at a time and dropped down a plant tube.
4) A complete row of plants are mechanically ejected from the containers and into a plug retaining belt which swings away from the containers, separating the row of plants and then indexing forward and dropping one plant at a time into a drop tube.
In all of these approaches it is important to clearly separate the foliage from the plant to be dropped from the remaining stationary plants immediately above, and is a prerequisite to the unhindered proper handling of an individual plug and plant to be accurately placed in the ground.
In the type of planter that transfers an entire row of plants into a plug retaining belt which then swings away, separating the plants to a lower region, and then dispensing the plants one at a time, the speed of the machine in terms of continuous, uninterrupted plants evenly spaced in the field, is determined by the time it takes for the plug retaining belt to swing up, be loaded and return to the planting position. This has been partly addressed in the aforesaid Williames International Patent Application No. PCT/AU97/00893 by dispensing a plant on the conveyor upswing before loading another row of plants.
A common problem with all planting machines is that plants are often grown in clay type soil which stick, to and build up on, the soil opening device causing a wide trough or groove to be formed in the soil. This allows the transferred plug and plant to be placed in an uncontrollable manner and position. This precludes the possibility of property compressing the soil around the plug.
It is an object of this invention to address the foregoing problems and requirements either individually or together as a whole for improved or proper handling and placement of plugs and plants and further to preferably have the ability for the farmer and market gardener to meet the many and varied demands often present on the one farm, and even within the one field. Desirably transplanting apparatus needs to respond to the many and varied circumstances encountered by a contractor who usually transplants on a number of farms in widely variable circumstances.
The invention provides for a machine with fast interchangeable clip/pin or bolt on attachments as a unique system that improves the handling and placement of plugs and plants regardless of the substantial variations and conditions. These variations and conditions include the following:
1) Soil types and conditions; fine dry powdery soil, loose soil, heavy clay soil, wet sticky soil, muddy soil, firm and hard soil, cloddy soil, soil mixed with vegetative materials, e.g. grasses and trash from previous crops.
2) Plant and plug conditions; tangled plants, tall single stemmed plants e.g. tomatoes and peppers, multi stemmed tall plants e g. onions and leeks, broad foliage plants e.g. lettuce and celery, semi dry plugs, saturated plugs and plants, wind-buffeted plants and knocked down plants.
3) External variables: very hot and dry conditions, windy conditions, rain, formed beds, unformed beds, uniform beds, mulch planting beds with bed covering, including plastic sheet.
When such plants as, brassica, cauliflower, broccoli, cabbage, are grown in close proximity to each other, they tend to xe2x80x98zip lockxe2x80x99 to each other, the stems criss-cross and the rounded bud of the leaves grow in behind the adjacent stems interlocking the individual plants to their neighbors.
Tomatoes, although they grow on a relatively vertical stem, have individual branches and leaves which curl out horizontally and down and around to form a hook. The formation of the leaf structure in combination with this hooking effect, causes the individual plants to act like a grapple, tenaciously intermeshing and hanging on to the adjacent plants. This invention, in one aspect, provides an improvement for separating individual plants by means of a rotating comb. A major improvement includes a means of retaining a plug in a plug retainer and combining with close tolerance to a curved backboard. This assures that the plug is very substantially restrained and that the plant top cannot escape from the path of the rotating comb finger which forcibly passes between the plant stems and disentangles the interlocked foliage. This leaves the adjacent plants absolutely free from any entanglement or hindrance to proper handling.
To ensure that an even and regular supply of plants are available on an individual basis for continuous high speed planting, this invention, in accordance with another aspect, provides for automatic machines that include mechanical plug retaining systems containing a complete row of transferred plants. It is the aim of this invention to not only dispense one or more plants on the upward swing of the feed conveyor to reload, but also to dispense a second plant or plants on the swing down after having loaded and prior to coming to rest at the fully down, normal plant dispensing position. By this means, a normal machine plug conveying mechanism will swing up, load and swing down in 750 milliseconds. This means that the dispensing conveyor will have dispensed a plant immediately prior to the upswing, a further plant on the upswing, a further plant immediately after loading and commencing down swing, and another plant immediately when required when returned to the fully down dispensing position. Considering that the first, second and third plants have been dispensed in 750 milliseconds, this equates to 250 milliseconds between the dispensing of each plant, which will give an effective planting rate of four plants per second which is a major improvement on all existing mechanical transplanters.
To allow the control of plants that have been individually dropped whether it is by hand, from semi-automatic or fully automatic transplanters, this invention provides, in a still further aspect, a dual path for a secondary/alternative plant storage system. This ensures continuity and proper timing of plants for uniform plant spacing during the interchange between rows of plants on an automatic machine, or transfer of trays on semi-automatic or manual machinery.
This invention provides for the combing, dispensing and dual path control to be mounted at a very short distance from the horizontal plant handling transfer into the soil. This means that the drop time from plant discharge from whatever means, is less than 250 milliseconds regardless of the size and moisture content of the plug and the size and length of the plant foliage and will, as described above, plant four plants per second. This ensures proper control of the handling and placement of plants at four plants per second without missing intermittent plants at high planting speeds or risking overlap causing a doubling up of plants, placing two plants together with a subsequent gap.
This mechanism is directly coupled to the soil-opening shoe. This invention provides for being either a fixed shoe, adjustable width shoe or rotating discs which prevent the build up of mud and allows a clean uniform width of soil opening to receive the proper placement of the plug and plant. It also provides for an automatic mud scraping system on the sides of a planting shoe to work properly in muddy and sticky conditions.
This invention provides, in another aspect, for a push device which protrudes beyond the rear edge of the planting shoe and pushes the plug back into the point of closure of soil behind the shoe even during high speed planting. This push device is controlled by and attached to a pneumatic cylinder and roller guide system well above the level of contamination from the soil. This ensures free running and high speed planting. It is also interconnected with a horizontal plate that ensures mechanical separation of plants that are in the process of being planted from the plant that is immediately following. It is also self-cleaned on retraction. This plate is also positioned to push on the foliage of the plug being planted at the same time as the base of the pushing mechanism pushes on the plug, which prevents overturning from inertial forces during the ejection of the plug from the shoe into the soil.
This invention provides, in another aspect, for a special shaped pushing mechanism to push on the plug without engaging the soil that is closing and enveloping the sides of the plug. It provides for a spring-loaded hinged mechanism for shoe internal cleaning and flushing. The roller system for guidance and smooth linear transfer, and the pneumatic cylinder, whose speed can be varied to control inertial effect and allow the instantaneous planting controlled by the precise distance traveled, thus ensuring the absolute accuracy and uniformity of plant spacing, plant to plant along the row regardless of the prime mover and planter speed variation.
The invention also separately provides for a unique means of completely containing a plug and seedling to ensure that it is in the correct location vertically, and free from any influence from the passage of soil and external wind. By using vertical twin doors to which a dud ejecting deflector, in one embodiment of the invention, can be fitted to an upper portion of one door, allows for the sorting of plugs not containing a plant and very rapid opening of the complete rear aperture of the planting shoe. This allows the passage of the highest plants with no additional delay regardless of the height of the plant. As the doors are on a vertical axis they are able to close quickly behind the planted plant without impinging on the plants upper foliage and be ready to receive the second plant. By this means concise control of the plants can be maintained while planting at very high speeds. The means are also provided for the pushing assembly to be self-leaning on retraction.
For high speed planting it is desirable to ensure that the open furrow behind the soil-opening device is closed evenly and consistently around the planted plug and plant. This is achieved, in one preferred embodiment, by a pair of pneumatic smooth skinned tires, ribbed tires or conical shaped wheels. These tires or conical shaped wheels are fitted to an adjustable framework allowing the position and angle of the wheels to be adjusted as follows
1. The wheels can be moved backward and forward to alter the distance between the wheels and the soil opening device, depending on the soil type and condition to ensure the proper movement of soil to envelop the plug.
2. The vertical plane of the wheels can be rotated about an axis to allow the top of the wheels to be a greater distance apart than at the base. This arrangement when using a small diameter wheel and held in an inclined plane, will roll in a substantial amount of soil and compact it completely around the plug, the amount of soil being moved being proportionate to the type of soil and the vertical angle of the wheels or cones.
There is also provision where it is necessary to have extreme control of the placement of the plant relative to the surface of the soil and to have a flat bed, for example, planting lettuce, it is necessary in one preferred embodiment, to have a tandem set of small diameter wheels, each pair or series of wheels being longitudinally and independently mounted on a rocker assembly which provides a stable load carrying assembly. An added advantage of using small diameter wheel is that it allows for close proximity machine to machine for close row spacing planting. The smaller radius of the front pair of vertically inwardly sloping wheels provides an adjustable means of varying the amount of soil being transferred inwardly and compressed around the plug. The second rear pair of wheels provide increased flotation and can be fitted, in one preferred embodiment, with cone shaped wheels. These wheels are adjustable on their axis to provide the placement of the inner edge of the lower portion of the cone in the desired location relative to the plant and plug. The angle of these cone shaped wheels can be adjusted to any desired bed shape including an absolutely flat bed. This assembly is also vertically adjustable and because of the tandem action and wide spread support enables precise depth control of the placement of the plant relative to the surface of the soil by maintaining a precise location of the planting mechanism relative to the surface of the soil.
The scope of the inventive aspects as defined herein are as set out in the annexed claims or as defined in any aspect or feature of the current description. The annexed claims should be regarded as part of the present disclosure.